Both my grandmothers shortly passed after minor falls but enough to break bones at their age. One, and maybe both if I recall, broke their hips, which is a lot worse than ribs. Darth Bader is so frail, that I know for sure she is at home and in a lot of pain, but I suppose it’s possible she’ll be ok.
I’d be shocked if she resigns under any circumstances. I can see her taking sick leave though the 2020 elections if she lives that long. She will use every last breath of hers to keep Trump from filling that seat.